Inhibitory Effects of Beta-herpesviruses on Hematopoiesis

人类疱疹病毒6型(HHV-6)和人类巨细胞病毒(CMV)与广泛应用免疫抑制药物的造血干细胞移植(SCT)后的各种严重并发症有关。我们监测了异基因SCT后包括三种β-疱疹病毒在内的五种疱疹病毒的活性，发现HHV-6与SCT后造血细胞植入延迟有关。然而，体外模型还没有证明β-疱疹病毒与临床表现之间的关系，我们建立了体外系统来评估HHV-6和相关的β-疱疹病毒对造血集落形成的影响。我们对比检测了HHV-6A、HHV6B和人类疱疹病毒7型(HHV-7)。我们发现这两种类型的HHV-6在体外都能抑制红系(BFU-E)、粒/巨噬细胞(CFU-GM)和巨核细胞(CFU-Meg)这三种造血祖细胞系的形成。另一方面，HHV-7在体外对HEMA…没有任何抑制作用我们专注于HHV-6B，并进一步研究了与人CD34+细胞的相互作用，CD34+细胞是造血祖细胞的主要来源。用免疫磁珠法从脐血单个核细胞中分离CD34+细胞，用抗CD34+抗体包被在动态珠子或Mac珠子上。用DYNABEADS选择的CD34+群体显示出广泛的荧光。用MACS珠子选择的人群显示出很小范围的荧光。在感染HHV-6后，在两个细胞群中都检测到了即刻早期基因的两个转录本。HHV-6对BFU-E、CFU-GM和CFU-Meg的集落形成有抑制作用。在血小板生成素(TPO)存在下，HHV-6在培养3~7天后抑制细胞生长。分化程度越高的CD34+细胞对HHV-6的影响越敏感。这些数据表明，HHV-6抑制造血的目标是在异质细胞群中表达较低数量的CD34抗原的相对分化的细胞(DIM细胞)。较少

Human herpesvirus 6 (HHV-6), as well as human cytomegalovirus, is related to various severe complications after hematopoietic stem cell transplantation (SCT) under extensive use of immunosuppressive drugs. We monitored the activity of five herpesviruses including three beta-herpesviruses after allogeneic SCT, and showed that HHV-6 is associated with delayed engraftment of hematopoietic cells after SCT. In vitro models, however, have not proven the relationship between beta-herpesviruses and the clinical manifestations.We established the in vitro systems to assess the effects of HHV-6 and related beta herpesviruses on hematopoietic colony formation. We comparatively examined HHV-6A, HHV6B, and human herpesvirus 7 (HHV-7). We showed that both type of HHV-6 suppresses all three lineages of hematopoietic colony formation of erythroid (BFU-E), granulocyte /macrophage (CFU-GM), and megakaryocyte (CFU-Meg) in vitro. On the other hand, HHV-7 did not have any suppressive effect on in vitro hema … More topoietic colony formation..We focused on HHV-6B and further examined the interaction with human CD34+ cells, which are a major source of hematopoietic progenitor cells. CD34+ cells were immunomagnetically isolated from cord blood mononuclear cells using anti-CD34+ antibodies coated onto either Dynabeads or MACS beads. The CD34+ population selected with Dynabeads showed a broad range of fluorescence. The population selected with MACS beads showed a narrow range of fluorescence. After infection with HHV-6, Two transcripts of the immediate early genes were detected with both cell populations. HHV-6 suppressed colony formation of BFU-E, CFU-GM, and CFU-Meg. HHV-6 suppressed cell growth after 3 to 7 days culture in the presence of thrombopoietin (TPO). More differentiated CD34+ cells were more susceptible to the effects of HHV-6. These data indicate that the targets for hematopoietic suppression by HHV-6 are relatively differentiated cells that express a lower amount of the CD34 antigen (dim cells) among a heterogeneous cell population. Less